first_last_agg
first() and last() aggregate functions
Repository
wulczer/first_last_agg
https://github.com/wulczer/first_last_agg
Source
first_last_agg-0.1.4.tar.gz
first_last_agg-0.1.4.tar.gz
Overview
| Package | Version | Category | License | Language |
|---|---|---|---|---|
first_last_agg | 0.1.4 | FUNC | PostgreSQL | C |
| ID | Extension | Bin | Lib | Load | Create | Trust | Reloc | Schema |
|---|---|---|---|---|---|---|---|---|
| 4710 | first_last_agg | No | Yes | No | Yes | No | Yes | - |
| Related | aggs_for_arrays aggs_for_vecs topn quantile lower_quantile count_distinct arraymath |
|---|
Version
| Type | Repo | Version | PG Ver | Package | Deps |
|---|---|---|---|---|---|
| EXT | MIXED | 0.1.4 | 1817161514 | first_last_agg | - |
| RPM | PIGSTY | 0.1.4 | 1817161514 | first_last_agg_$v | - |
| DEB | PGDG | 0.1.4 | 1817161514 | postgresql-$v-first-last-agg | - |
Build
You can build the RPM packages for first_last_agg using pig build:
pig build pkg first_last_agg # build RPM packages
Install
You can install first_last_agg directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:
pig repo add pgsql -u # Add repo and update cache
Install the extension using pig or apt/yum/dnf:
pig install first_last_agg; # Install for current active PG version
pig ext install -y first_last_agg -v 18 # PG 18
pig ext install -y first_last_agg -v 17 # PG 17
pig ext install -y first_last_agg -v 16 # PG 16
pig ext install -y first_last_agg -v 15 # PG 15
pig ext install -y first_last_agg -v 14 # PG 14
dnf install -y first_last_agg_18 # PG 18
dnf install -y first_last_agg_17 # PG 17
dnf install -y first_last_agg_16 # PG 16
dnf install -y first_last_agg_15 # PG 15
dnf install -y first_last_agg_14 # PG 14
apt install -y postgresql-18-first-last-agg # PG 18
apt install -y postgresql-17-first-last-agg # PG 17
apt install -y postgresql-16-first-last-agg # PG 16
apt install -y postgresql-15-first-last-agg # PG 15
apt install -y postgresql-14-first-last-agg # PG 14
Create Extension:
CREATE EXTENSION first_last_agg;
Usage
first_last_agg: first and last aggregate functions for PostgreSQL
Provides first and last aggregate functions that return the first or last value in a group, operating on any element type.
CREATE EXTENSION first_last_agg;
Functions
| Function | Description |
|---|---|
first(anyelement) | Return the first value in the group |
last(anyelement) | Return the last value in the group |
Examples
-- Get the first and last values (use ORDER BY for deterministic results)
SELECT id, first(val ORDER BY ts), last(val ORDER BY ts)
FROM events
GROUP BY id;
-- Without ORDER BY, the ordering within groups is undefined
SELECT department, first(salary ORDER BY hire_date)
FROM employees
GROUP BY department;
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